Method of producing redispersible fibers and mat product



METHOD OF PRODUCING REDISPERSIBLE FIBERS AND MAT PRODUCT D. LABINO Dec.24, 1963 Original Filed Nov. 29, 1954 INVENTOR. DommcK LABINO UnitedStates Patent ()fifice 3,114,939 Patented Dec. 24, 1963 $114339 METHODOF PRODUCKNG REDISPERdIBLE FIBERS AND MAT PRUDUCT Dominick Labino, GrandRapids, Ghio, assignor to JGllilllS-r Manville Corporation, New York,N.Y., a corporation of New York Continuation of application Ser. No.471,695, Nov. 29, 1954. This application Nov. 29, 1960, Ser. No. 72,45613 Claims. ((11. 19156.3)

This invention relates to the production of mats of fibrous materials,and to the packaging thereof; more specifically the invention relates tothe production of thin, light-weight fibrous mats of glass fibers, thecoherency of the fibers of which mats is such that the fibers areredispersible in gaseous media, particularly air.

This application is a continuation of my co-pendmg application SerialNo. 471,695, filed November 29, 1954, now abandoned.

Mats of siliceous or glass fibers are customarily formed by feedingfilaments of siliceous material into a hot gas blast which serves toattenuate the filaments into fine fibers of short lengths. These fibersunder the force of the blast are dispersed and may be collected in matform on a surface moving transversely to the blast.

The fibers as they collect on the surface tend to form a woolly mat, andto secure a compact mat it is customary to wet the same as it is formedby spraying resinous materials, or water, on the fibers and/or matsurface. Wetting the surface tends .to compact the mat which is thenpackaged by rolling in paper or other suitable mater-ialthe adjacentplies of mat being separated by the packaging material.

The packaging material is necessary for the dried fibers of adjacentlayers would cohere and prevent satisfactory unrolling of the mats.

It has been found to be desirable in some instances to redisperse theglass or siliceous fibers of a mat in a suspending gaseous medium suchas air but even the watertreated mats have not been successfullyemployable for this purpose as the compaction occasioned by the water issufiicient to provide an undue coherence of the fibers of the mat evenwhen the same has been thoroughly dried.

It is a primary object of this invention to describe a novel procedurefor the production of light-Weight mats of siliceous fibers whichprocedure enables the production of mats the fibers of which areredispersible in gaseous media.

It is an important object of this invention to describe a novel processfor the formation of light-weight mats which procedure eliminates thenecessity of a packaging material between adjacent plies of the mat.

It is a particular object of this invention to describe a novel matproduct of siliceous fibers.

In the production of mats of siliceous fibers, the fibers of which it isdesired to redisperse, it has been found that if, in the course of theformation of the fibers and of the mats themselves, the same are notwetted then redispersion in gaseous media is materially facilitated.

It appears that even a wetting with water followed by thorough drying issufficient to increase the degree of coherence of the fibers such thatthey do not readily redisperse; however, if the fibers as they areblown, are maintained dry or simply free of wetting agents, the unwettedmats may have the fibers thereof redispersed in a current of air forexample.

It has further been found that if the dry fiber mats are subjected to apressure, most suitably a light pressure, that the fibers of a layer ofmat tend to cohere to an extent sufficient to permit the mat to berolled or layered directly upon itself, and that the layers arethereafter 2 readily separable from each other Without disruption of themat form. That is, the fibers of adjacent layers, will not coherematerially and thus the necessity for rolling the mats in othermaterials, such as paper, is eliminated.

The elimination of the paper etc. simplifies the winding process, alsothe unwinding process and lends to economy of both packaging andshipping.

The mats of this invention are web-like in thinness and most suitablyhave a weight per square yard of between 15 to 60 grams although mats ofglass fibers of a weight as low as 8 grams per square yard have beensuccessfully manipulated. As the weight per square yard increases aboveabout 60 grams the redispersibility of the fibers becomes moredifi'icult simply due to the bulk of the mat.

The invention will be more fully understood by reference to thefollowing detailed description and accompanying drawings wherein:

FIG. 1 is a schematic representation of apparatus useful in the practiceof the invention;

FIG. 2 is a side elevational view of a portion of the apparatus of FIG.1;

FIG. 3 is a plan view of the structure of FIG. 2;

FIG. 4 illustrates the product of the inventive process in rolled form;and

FIG. 5 illustrates a plurality of mats, made according to the process ofthis invention, stacked in laminar fashion.

Referring to the drawings there is shown at 1 in FIG. 1 a glass meltingpot composed of platinum or a suitable alloy as platinum-rhodium forexample. Pot .1 is surrounded with insulation material 3 and providedwith a heating element, such as an induction coil 5, supplied withenergy from a suitable source (not shown).

Pot it retains a body of molten glass 7 which exudes through apertures sin the base of the pot to be drawn into filaments 11. Filaments 11 passover a guide roll 13 and are presented in substantially parallelrelation to drawing rolls 15.

Below the drawing rolls and le'ftwardly (FIG. 1) is a burner 17 fromwhich emanates a hot gaseous blast 19; the gaseous blast strikes theparallel-arranged filaments as they pass the lower end of guide 20 andthe filaments are blown toward hood 21 and highly attenuated into finefibers 23 of relatively short length.

At the right hand end of the hood 21 a wire mesh or perforated belt 25passes upwardly, closes the hood end and receives the blown fibersthereon. The belt is itself continuous and adapted to be trained overrolls indicated at 2'7, 29, 31, the latter of which is driven throughmeans which include motor 28, sprockets 30, 32 and chain 34.

Mounted in any suitable manner within the belt is a sheet metal housing33 which provides an open end 35 closely adjacent the belt for thedevelopment of a vacuum pressure at the belt surface. A conduit 36 isprovided in the rear of the housing for the exhaustion of air by anappropriate motor and vacuum pump combination.

The fibers 23 under the influence of the blast and the vacuum pressureat the moving belt surface deposit in a thin web or mat on the belt andare carried upwardly. The thickness and weight per square foot of theweb are easily controllable by simply moving the belt at greater orlesser speeds and in accordance with the rate of glass filament feed tothe burner. Rightwardly, supported slightly above the surface of thelonger strand of the belt, is a roller or simply a statiouary rod 37which engages the underside of the web and lifts the same in order thatit may be drawn to the pressuring and winding equipment indicatedgenerally at 39.

As shown in FIG. 1 a relatively large support roll 41 is provided toreceive the web. Roll 41 is provided with a sprocket 42 which isconnected with motor 28 by chain 40 and sprocket 38. Roll 41 ispreferably driven at a speed slightly in excess of that at which the matis formed and accordingly there is imparted thereby a slightly draftingaction whereby the mat is stretched slightly to efiect an orientation ofthe fibers. Roller 43 suitably bears under the influence of gravity uponthe driven roll 41 and pressures the mat. The pressuring action issupplemented by the drafting action which also aids in causing thefibers to lie down smoothly.

Rolls 45, 47 are similar to roll 41 and are suitably provided withsprockets and chains for driving from and in synchronism with roll 41.The roll 49 rotates freely and is spaced sufiiciently from roll 41 inthe direction of rolls 45, 47 to permit effective drafting to take placeas the mat stretches out.

Rolls 45, 47 are each provided with pressure rolls 51, 53, respectively,and the mat issuing rightwardly is wound while supported on suitablydriven rollers 55, 57 without the interposition of paper or otherseparating material.

The uniformity of thickness of the mats 7% of this invention isimportant both in connection with fiber redispersal and the rolling ofthe mats '70. The uniformity is generally more difficult to attain asthese thin mats become very wide and there is a distinct tendency forthe mat edges to be thinner than the center when a single gas blast isemployed; with a plurality of gas blasts issuing from a like pluralityof burners, such are sometimes employed on very wide mats, the resultantmat may even be ridged.

As shown in FIGS. 2 and 3 the housing 33 may be provided internally witha plurality of built-in guides to accommodate a series of panels whichare each wholly or partially insertable into the air stream flowing fromthe open end 35 of the housing to the conduit 36. The guides, indicatedat 59, 61, 63, respectively, engage panels 65, 67, 69 frictionally. Thepanels are separately vertically movable into the guides and therelationship between the extent of the insertions of each determines thepressure condition across the belt face (FIG. 1). Accordingly the panelsserve to regulate the fiber deposition and to provide for matuniformity.

The freshly Wound roll of mat 79 is indicated at 71 in FIG. 4 and whilefiufiiness is present quite unexpectedly the same does not restrict theredispersal of the fiber of the mat. The redispersal is itself benefitedmost particularly by the absence of wetting of the fibers of the mat;the packaging of redispersible fibers is benefited both by the absenceof the wetting and the pressuring of the mat as it is being packaged.

While the invention has been described in particularity with relation asto a redispersible roll package, it will be understood that theinvention also finds utility in the formation of a selfsustaining mat,for use as an intermediate product in a process which may besubsequently dispersed. It is also contemplated that a plurality of mats70 of this invention may be stacked or layered in laminar fashion andsubsequently be redispersed into individual layers without destroyingthe integrity of the layers.

It will be understood that this invention is susceptible to modificationin order to adapt it to different usages and conditions and accordinglyit is desired to comprehend such modifications within this invention asmay fall within the scope of the appended claims.

What I claim:

1. A method of forming an unwoven siliceous fibrous mat, comprising incombination: melting a supply of siliceous material; forming fine fibersfrom the melt; dispersing the formed fibers in a gaseous stream;collecting said fibers as a substantially uncompressed Web; andsubjecting the resultant web to a simultaneous stretching andcompressing step to orient the fibers thereof without subjection tointermediate compression.

2. The method as described in claim 1 which comprises the further stepof subsequently rolling said web upon itself.

3. A method of forming a redispersible package of un woven siliceousfibrous mat comprising in combination: melting a supply of siliceousmaterial; forming fine fibers from the melt; dispersing the formedfibers in a gaseous stream; collecting said fibers as a substantiallyuncorn pressed web; subjecting the resultant web to a simultaneousstretching and compressing step to orient the fibers thereof withoutsubjection to intermediate compression; and subsequently layering aplurality of said webs contiguous to each other to form a laminatecomprised solely of said Webs.

4. A method of forming a redispersible package of unwoven siliceousfibrous mat, comprising in combination: attenuating simultaneously aplurality of continuous siliceous filaments into fine fibers with a hotgaseous blast to form hot dry fibers; collecting said fibers as asubstantially uncompressed Web; subjecting the resultant web to asimultaneous stretching and compressing step to orient the fibersthereof without subjection to intermediate compression.

5. The method as described in claim 4 which comprises the further stepof subsequently rolling said Web upon itself.

6. A method of forming a redispersible package of unwoven siliceousfibrous mat comprising in combination: melting a supply of siliceousmaterial; forming fine fibers from the melt; dispersing the formedfibers in a gaseous stream; collecting said fibers as a substantiallyuncompressed web; subjecting the resultant web to a simultaneousstretching and compressing step to orient the fibers thereof withoutsubjection to intermediate compression; and subsequently layering aplurality of said webs contiguous to each other to form a laminate.

7. A method of forming a redispersible roll of unwoven siliceous fibrousmat having a substantially uniform density, comprising in combination:simultaneously attenuating a plurality of continuous siliceous filamentsinto fine fibers with a hot gaseous blast; collecting said fibers underthe influence of said blast and a source of vacuum as an uncompressedweb; regulating the vacuum applied across the width of the web beingformed to provide a web having a substantially uniform thickness;subjecting the resultant web to a simultaneous stretching andcompressing step to orient the fibers thereof without subjection tointermediate compression.

8. A method of forming a redispersible roll of un- Woven siliceousfibrous mat having a substantially uniform density, comprising incombination: simultaneously attenuating a plurality of continuoussiliceous filaments into fine fibers with a hot gaseous blast;collecting said fibers under the influence of said blast and a source ofvacuum as an uncompressed web; regulating the vacuum applied across thewidth of the web being formed to provide a Web having a substantiallyuniform thickness; subjecting the resultant Web to a simultaneousstretching and compressing step to orient the fibers thereof withoutsubjection to intermediate compression; and subsequently rolling saidweb upon itself.

9. A method of forming a redispersible roll of unwoven siliceous fibrousmat having a substantially uniform density, comprising in combination:simultaneous- 1y attenuating a plurality of continuous siliceousfilaments into fine fibers with a hot gaseous blast; collecting saidfibers under the influence of said blast and a source of vacuum as anuncompressed web; regulating the vacuum applied across the Width of theweb being formed to provide a web having a substantially uniformthickness; subjecting the resultant web to a simultaneous stretching andcompressing step to orient the fibers thereof without subjection tointermediate compression; further subjecting the resultant web to atleast one compressing step.

10. A method of forming a redispersible roll of unwoven siliceousfibrous mat having a substantially uniform density, comprising incombination: simultaneously attenuating a plurality of continuoussiliceous filaments into fine fibers with a hot gaseous blast;collecting said fibers under the influence of said blast and a source ofvacuum as an uncompressed web; regulating the vacuum applied across theWidth of the web being formed to provide a web having a substantiallyuniform thickness; subjecting the resultant Web to a simultaneousstretching and compressing step to orient the fibers thereof withoutsubjection to intermediate compression; further subjecting the resultantWeb to at least one compressing step; and subsequently rolling said webupon itself.

11. A redispersible unwoven siliceous fibrous package comprising aplurality of adjacent fluify non-cohering layers, each of said layersconsisting of a plurality of dry oriented siliceous fibers.

12. A flufi'y siliceous fibrous mat consisting of a plurality oforiented fine dry siliceous fibers, said mat having 6 a weight ofbetween about 8 to 60 grams per square foot.

13. A siliceous fibrous package comprising a plurality of flutfycontiguous layers, each of said fluffy layers consisting of a pluralityof oriented fine dry siliceous fibers, said fibers being sufiicientlycoherent in respect to other fibers within a layer to form the layer,and said layers being sufiiciently incoherent in respect to each otherto maintain the integrity of the individual layers when separated fromeach other.

References Cited in the file of this patent UNITED STATES PATENTS1,864,317 Powell June 21, 1932 2,318,244 McClure May 4, 1943 2,518,744Barnard Aug. 15, 1950 2,787,542 Labino Apr. 2, 1957

1. A METHOD OF FORMING AN UNWOVEN SILICEOUS FIBROUS MAT, COMPRISING INCOMBINATION: MELTING A SUPPLY OF SILICEOUS MATERIAL; FORMING FINE FIBERSFROM THE MELT; DISPERSING THE FORMED FIBERS IN A GASEOUS STREAM;COLLECTING SAID FIBERS AS A SUBSTANTIALLY UNCOMPRESSED WEB; ANDSUBJECTING THE RESULTANT WEB TO A SIMULTANEOUS STRETCHING ANDCOMPRESSING STEP TO ORIENT THE FIBERS THEROF WITHOUT SUBJECTION TOINTERMEDIATE COMPRESSION.